Conventionally, shunt resistance-type current sensors have been proposed which, to detect a pulse current, a large AC current, or the like, detects the magnitude of a measurement subject current by causing the measurement subject current to flow through a shunt resistance portion whose resistance is known and detecting a voltage drop across the shunt resistance portion. For example, a metal piece called a busbar may be used for power distribution in vehicles such as automobiles, in which case a portion of the busbar which functions as a current path is used as a shunt resistance portion. A circuit board is disposed over the busbar. To detect the magnitude of a measurement subject current flowing through the busbar, the circuit board is mounted with a voltage detection IC for detecting a voltage across the shunt resistance portion.
In shunt resistance-type current sensors of this type, the resistance of the shunt resistance portion may vary depending on the temperature. Therefore, shunt resistance-type current sensors detect a temperature of the shunt resistance portion and correct a resistance value according to the detected temperature. In particular, where the shunt resistance portion has a large temperature dependence coefficient, it is necessary to detect a temperature of the shunt resistance portion correctly. To this end, the circuit board that is mounted with the voltage detection IC for detecting a voltage drop and other components is also mounted with a temperature sensor (refer to Patent document 1).